Preparation and performance of resin-bonded grinding wheel with braze-coated diamond grits

The use of braze coating is proposed to obtain a layer of filler alloy on different types of diamond grits for improving diamond grit retention in resin-bonded diamond wheels. The effects of brazing on surface morphology and mechanical properties of diamond grits were evaluated. Resin-bonded diamond wheels with braze-coated diamond grits were prepared, and the grinding performances of cemented carbide wheels with different diamond grits were tested. Brazing could successfully cover most of the diamond grits with a layer of filler alloy. Pores and bumps of several microns in size were observed as well as the formation of titanium carbide (TiC) between the coating and diamond grit. Toughness indexes (TIs) of coated single-crystal diamond grits (RVD) decreased only slightly, but significantly increased for coated polycrystal diamond grits (PDGF1). The wheel containing coated PDGF1 diamond grits exhibited the lowest grinding forces and highest grinding ratio among the four wheels evaluated, whereas the wheel with coated RVD diamond grits produced the highest grinding force and a relatively low grinding ratio.